Coal-drill bit



(No Model.)

' D. CORGAN.

GOA L DRILL BIT.

No. 381,114. Panama Apr.'17, 18.88.-

N. PETERS me um n hu. w=

UNITED {STATES} PATENT OFFICE.

- DANIEL CORGAN, OF LUZERNE, PENNSYLVANIA.

.COAL-DRILL err.

SPECIFICATION forming part of Letters Patent No. 381,114, dated April17, 1888.

Application filed August 2, 1887. Serial No. 245,961. (No model.)

To 00% whom it may comer-n).-v

Be it known that I, DANIEL CORGAN, acitizen of the United States,residing at Luzerne, in the county of Luzerne and State of Pennsylvania,have invented a new and useful 1m provement in Coal-Drill Bits, of whichthe following is a specification.

My invention relates to an improvement in coal-drill bits for use inblasting; and it con sists in the peculiar combination and arrangementof devices, which will be more fully hereinafter described, andparticularly pointed out in the claims.

In the accompanying drawings,wherein like letters of reference indicatesimilar parts in the several views, Figure 1 is a side elevation of adrilling apparatus with my improved drillbit shown in connectiontherewith. Fig. 2 is a detail perspective view of my improved form ofbit. Fig. 3 is a top plan view thereof.

Fig. 4 is a bottom plan view; and Fig. 5 is atransverse section on theline a: m, Fig. 2.

A indicates the auger, B the screw-rod connected thereto, and O thehand-brace for operating the several parts.

D indicates a brace rod or lever, one end of which is embedded in thecoal, the other end of said lever being provided with a suitable joint,d, which is connected to the depending arm e of a screw-block, E,through which the screw-rod B passes.

My improved form of bit, F, is secured to the end of the augerstem A anditcon'sists, essentially, of the two plates ff, arranged to form theupper and lower plates of the bit. The plate f is constructed incurvilinear form, having an enlarged convexity at its central portion,with edge flutes f r The plate f is straight, and the depressions of theplate 7, formed by the flutes f, rest thereagainst. The edges of each oftheplates f and f are flared upwardly, and then slightly bent downwardand upward, as at f and f, to form guides for the side cutters, G G. Therear ends of. the

said side cutters, G,are braced against rear- 7 ward displacement bystop blocks or stripsf secured between the edges ofthe rear portion ofthe flanged. edges of the plates f and f. The two plates f and f areriveted together and firmly held in engagement.

The side cutters, G, project outwardly from the front edges of theplates 7 and f, having oppositely-inclined -cutting-edges f, each ofwhich terminates in the reversely bent points In the central cavityformed by the union of the two plates f f the central cutter, H, ismounted and projects out from the said plates between the edge cutters,G, and some distance beyond the same. The cutter H is held in permanentposition by a set-screw, h, passing through the said plate and thecutter. A wedge-shaped spur, h, is integrally formed with one sidethereof, which bears against the front edge of the plates f f", therebylimiting the rearward movement of the cutter and serving to break andcrush the coal, as will be hereinafter set forth. The cutting-point ofthis cutter H consists, essentially, of an incline, h", extending fromone side to the other and terminating h h 4 In the use of my improvedbit the central cutter, H, strikes into the coal or other material firstand enters the same some distance before the edge cutters, G, come intoplay. By means of these central and edge cutters concentric holes areformed with a wall of coal between them, the core being formed by theinner hole. As the bit advances into the coal, the spur h will break andcrush the wall between the inner and outer holes, and the core will beremoved by the action of the auger.

The advantage and utility of this manner of drilling will be readilyappreciated by those skilled in the art, and need not be furtherenlarged upon herein. 7

It is obvious that steam, hydraulic, or other power may be used with myimproved form of drill, and that various materials may be operated uponby the same.

Having thus described my invention, I claim--- 1. The combination of theflat plate f, the curved plate f, riveted to the upper side thereof, andthe cutter H, secured to the un= der side of the curved plate .by'aset=screw and provided with the wedge-shapedspur h,

resting against the front edges of the plates f f, substantially assetforth.

2. The combination of the plates I f f, riv

eted together and having their sidefedges h" h, formed at the one sideof its front beveled edge, h, and the wedge-shaped crushing-spur h, incombination with the edge cutters, G G, held by the plate F, asdescribed,substantiall y as set forth.

In testimony that I claim the foregoing as my 4 own I have heretoafiixed my signature in presence of two witnesses.

, DANIEL CORGAN. Witnesses: i

P. H. CAMPBELL, PHILIP ONEILL.

